Metal pulley with detachable plastic fan

ABSTRACT

A belt pulley assembly comprises a metal pulley element which is detachably combined with a plastic fan that contains an embedded metal disk having an inner exposed rim that is slotted along with the hub of the pulley element to receive a drive key.

[ 51 May 2,1972

United States Patent- Marsch S T. N m M. m mm NT. s mm H N U m H E m H mT E D H W m LN A F m AS A L MP m U 4/1951 Carlin et a1.....................74/230.0l X

[72] Inventor: Karl Mai-sch, Burgermeister-Siegler- Strasse 9,6842,Burstadt, Germany Dec.3,1970

[22] Filed:

[21] App1.No.:

France. 4,421,286 9/1966 Ja an 301 Foreign Application Priority DataDec. 6, 1969 Germany......................P 19 61 299.8 PrimaryExaminer-Le0nard H. Gerin Attorney-Harness, Dickey & Pierce ABSTRACT Abelt pulley assembly comprises a metal pulley element 1 7 5 LA nu NW 114 2 9 34 M1 Mm 3 0 3 2 4 C s U H 5 i which is detachably combined witha plastic fan that contains mm. 7 P2 0 P0 a 1 mm W N 6 n 3 wm 5 h 6 m0 13 m 9 ".2 h 1 mmm m&4 m H L m C l .M ale MF 11 8 55 an embedded metaldisk having an inner exposed rim that is slotted along with the hub ofthe pulley element to receive a drive key.

9 Claims, 2 Drawing Figures METAL PULLEY WITH DETACI'IABLE PLASTIC FANRELATED APPLICATION This application is based on West German patentapplication, Ser. No. P 19 61 299.8, filed Dec. 6, 1969. Priority isclaimed.

BACKGROUND OF THE INVENTION The coriventional method of producing suchbelt pulley assemblies consists in working the fan blade rim and thesupporting disk element as separate, pressed parts which are spot weldedtogether and then, e.g. by soldering or upsetting, uniting this subassembly with the belt pulley proper to obtain an inseparable unit.These belt pulleys have the drawback that in the case of any deformationthrough a fall or other improper handling, the edges of the fan bladerim will strike against the casing of the electric generator which inturn will cause the entire belt pulley to become spoiled.

In another conventional type of belt pulley assembly, a fan rim withblades made of thermoplastic material is spraymolded over an outer rimof a metal pulley body with a belt groove produced by non-chip forming,again to obtain a fixed and inseparable union. This type of belt pulleyis a material improvement in terms of increased durability andsimplified production of assembled belt pulleys.

SUMMARY OF THE INVENTION It is the purpose of this present invention tofurther enhance the durability and wear resistance of such belt pulleyassemblies, while at the same time maintaining as separate andindependently exchangeable construction elements both essential parts ofthe assembly, i.e. the disk element with belt groove and hub as well andthe separate fan blade rim.

This purpose is achieved in a preferred form of the invention by a fanrim with hub collar and fan blades, of a plastic material suitable fortransfer molding, being spray molded over and around a supporting sheetmetal disk with a borehole for the drive shaft and with a catch slot, insuch a way that said metal disk is fully enveloped in said material. Thehub of the pulley body with belt groove is constructed so that it may bepressed into the hub of the fan blade rim until it touches the inner rimof the supporting disk which later is openly visible in the area of thefront surface of the hub of the pulley body with belt groove; the unionthus obtained being secure but at the same time detachable. In this waythe two essential parts of the assembly are not only capable of beingseparately produced, but also of being separately stored as spare partsand easily exchangeable to further decrease the production cost of thisbelt pulley assembly.

Preferably, the fan blade rim should be equipped with cogs on the pulleyside opposing the belt groove; said cogs propping against the outersurface of the groove n'm. This will secure the mutual positioning ofthe two essential elements of the belt pulley.

It is also preferred that the fan blade rim with hub and blades be madeof a plastic material suitable for transfer molding (spray molding) tobe equal to any and all requirements in terms of shape of the fan bladerim. The resilience inherent in the plastic material also makes itpossible to obtain a securely clamped seat of the hub collar of the fanblade rim on the hub of the pulley body with groove, without impairingthe easy way of pressing-on and of detaching said collar. The drawbackfrequently observed in plastic material, i.e. the tendency to plastify(modifying its resilient quality) under pressure, is avoided in thisconstruction because of elimination of all such possible pressure areas.This is one of the reasons why the rim of the supporting disk juttingout to the inside remains freely metallic, i.e. is left without anyplastic coating, so that metal contacts metal at the surface of contactof the pulley hub with belt groove against the inner rim of thesupporting disk.

DESCRIPTION or 11112 DRAWINGS FIG. 1 is a cross section through a beltpulley assembly embodying the invention; and

FIG. 2 is a side elevation taken from the right of FIG. 1.

DESCRIPTION OF THE INVENTION According to FIG. 1 and FIG. 2 theassembled belt pulley includes two essential parts which are united inthe pulley but which may be detached from one another and usedindependently; i.e., the pulley element 1 with belt groove 2 and hub 3,and the fan blade rum 4 with the fan blades 5 and hub collar 6. Thepulley element 1 is preferably sheet metal or produced by a non-chipforming process, and permanently united with the hub 3 by conventionalmeans.

The fan blade rim 4 is made from non-metallic plastic material suitablefor transfer molding. It is produced by spraying the rim with blades 5and hub collar 6 over and around the sheet metal disk 7. By this processthe sheet metal disk 7 is entirely enveloped within the fan blade rim 4except its noncoated inner rim 8, the disk thus serving as a support forthe fan blade rim. The hub 3 and the sheet metal disk 7 have the samebore diameter 9 for the drive shaft (not shown in the illustration) andthe same key slot 10 for attachment to the drive shaft. In this way thesheet metal disk 7 serves as driver disk for the fan blade rim 4, thematerial of which fills the recesses 1 l in the sheet metal disk 7.

When assembling the two essential elements into the finished beltpulley, the fan blade rim 4 with its hub collar 6 is pressed onto theouter circumference of the hub 3 of pulley element 1 until the frontsurface of hub 3 comes into contact with the non-coated inner rim 8 ofsheet metal disk 7. In this end position the cams 12 disposed over thesurface of fan blade rim 4 opposed to pulley element 1 come into contactwith the outer surface 13 of the rim of belt groove 2, supporting thefan blade rim 4 against said surface.

The invention therefore provides an assembled belt pulley and fan forthe use in appliances such as electric generators for automotivevehicles that includes a sheet metal pulley element with a belt groovepreferably produced by a non-chip forming process, and having a hub, anda fan blade rim characterized by the following features: the fan bladerim 4 has a hub collar 6 and fan blades 5 that are spray-molded over andaround a supporting sheet-metal disk 7, that has a bore hole 9 for thedrive shaft and a driver key notch 10, to entirely envelop said sheetmetal disk 7. The hub 3 of pulley element 1 with belt groove 2 is thenpressed in a secure but detachable manner into the hub collar 6 of fanblade rim 4 to a depth where the front of the hub 3 of pulley element 1with belt groove 2 comes into contact with the non-coated rim 8 of thesupporting disk 7. In addition the fan blade rim 4 has cams orprojections on the surface opposing the pulley element 1 in contact withbelt groove member 2 in such a way that said cams 12 support said fanblade rim 4 against the outer surface 13 of the belt groove rim. Asindicated, the fan blade rim 4 with hub collar 6 and blades 5 arepreferably made of plastic, non-metallic material suitable for transfermolding.

This invention is not restricted to the construction example as abovedescribed and herein illustrated. Different construction models maybeadapted to suit the individual applications. The advantages of thisinvention-aside from facilitating the production of such belt pulleysand increasing their durability--also include facilitating ofinterchangeability of the construction elements of such assemblies, thepossibility of separate use of each of these elements, and the practicalwarehousing of each of said elements separately from one another.

I claim:

1. A belt pulley assembly comprising a metal pulley member having a beltgroove therein and a hollow hub and a nonmetallic plastic material fanmember, said fan member comprising a monolithic body having a hollowcollar portion and a metal disk embedded in the body having an innerannular rim projecting radially inside of the collar portion, said hubbeing telescoped inside the collar to a position adjacent said innerrim.

2. A device as set forth in claim 1 wherein .said hub and inner rim havea drive key slot means formed therein.

3. A device as set forth in claim 1 wherein said members are detachablyconnected together.

4. A device as set forth in claim 3 wherein said hub and inner rim havealigned drive key slots therein.

5. A device as set forth in claim 1 including means interconnecting saidmetal disk and plastic body to transmit torque

1. A belt pulley assembly comprising a metal pulley member having a beltgroove therein and a hollow hub and a non-metallic plastic material fanmember, said fan member comprising a monolithic body having a hollowcollar portion and a metal disk embedded in the body having an innerannular rim projecting radially inside of the collar portion, said hubbeing telescoped inside the collar to a position adjacent said innerrim.
 2. A device as set forth in claim 1 wherein said hub and inner rimhave a drive key slot means formed therein.
 3. A device as set forth inclaim 1 wherein said members are detachably connected together.
 4. Adevice as set forth in claim 3 wherein said hub and inner rim havealigned drive key slots therein.
 5. A device as set forth in claim 1including means interconnecting said metal disk and plastic body totransmit torque from the disk to the body.
 6. A device as set forth inclaim 5 wherein said means comprises recesses in the metal disk, theplastic of the body filling said recesses.
 7. A device as set forth inclaim 6 including means providing aligned key slots in the hub and innerrim.
 8. A device as set forth in claim 7 wherein said hub is detachablymounted in the collar.
 9. A device as set forth in claim 1 wherein saidbody has lateral stabilizing projections engaging said pulley member.